A short message service center ("SMSC") receives, stores and forwards short messages in a wireless telecommunications network. The short messages are originated and received by service users connected via the telecommunications network. Some examples of service users include mobile phones, pagers, location registers, terminal operators, personal computers and other short message service centers. Using a short message service center, a telecommunications network provider is able to provide valuable teleservices such as, for example, alphanumeric paging, informational messaging (e.g., providing users with stock quotes or sports scores), and program messaging (e.g., activating or re-programming a mobile station (e.g., phone or pager) remotely). However, as wireless telecommunications networks become more widespread and more integrated, conventional SMSCs will become a significant bottleneck.
Using conventional SMSCs in the integration of the different telecommunications networks presents a problem because they are not capable of differentiating between users within a specific type of service. Conventional SMSCs may differentiate between different types of service users (i.e., a mobile phone may be treated differently from a location register), but all service users within a specific type are treated the same. This may present a problem if, for example, two regionally disparate networks having widely disparate network delivery capacities are integrated. Using conventional SMSCs, the network provider would have to decide which network's capacity to use as a limiting factor in setting up the delivery characteristics of the SMSC. If the lower capacity network is chosen as the limiting factor, the higher capacity network is underutilized. If the higher capacity network is chosen as the limitation, the lower capacity network will be overloaded. Of course, one option would be to provide a separate SMSC for each network that is tailored to the capacity of that network, instead of a single SMSC. However, this would obviously impose additional startup, administrative, and maintenance costs.
Individual network delivery capacities also become an important factor during the processing of distribution lists. Distribution lists allow a service user to easily send a short message to a large number of users by setting up a distribution list specifying which service users will receive the short message the first time the user sends out a short message to those service users. Then, for future messages, the user merely needs to specify the distribution list as the recipient and the system will send the message to every service user included in the distribution list. A problem occurs if the distribution list contains a large number of recipients. The delivery capacity of a specific telecommunications network may not be sufficient to expeditiously send out all of the messages, thereby creating a bottleneck which may cause processing in the SMSC to grind to a halt until the delivery to the distribution list is complete. Conventional SMSCs take different approaches to solving this problem. In a first approach, nothing is done to avoid the problem, and the SMSC is allowed to effectively stall and is thus prevented from performing other tasks. In a second approach, service users are restricted from creating distribution lists beyond a predetermined size. This may force the user to create several lists when only a single large distribution list would suffice, which minimizes the benefits of having distribution lists in the first place. Thus, neither of these approaches provides a means of optimally processing distribution lists while allowing service users to realize the full benefits of distribution lists.
Another problem associated with integration is incompatibility of the short messages being transmitted in the various wireless telecommunications networks. Currently, the two major standard protocol definitions for short messages are ANSI 41 (variants of which are Time Domain Multiple Access ("TDMA") and Code Division Multiple Access ("CDMA")) and Global System for Mobile Telecommunications ("GSM") 03.40 specification (promulgated by the European Telecommunications Standards Institute ("ETSI")). These two protocols have different formats for short messages, and conventional SMSCs are incapable of delivering short messages from a service user on a network using ANSI 41 to a service user on a network using GSM, and vice versa. Thus, service users using one protocol are limited to recipients using the same protocol.
Integration using conventional SMSCs presents still another problem due to the different addressing systems used by the various telecommunications networks to identify their service users. For example, every service user must have a unique identification. In the wireless telecommunications field, this unique identification is called a Mobile Identification Number ("MIN ID"). When a first service user sends a short message to a second service user, the short message must contain the recipient's MIN ID to inform the SMSC of the identity of the recipient. Older networks use a commonly known method of addressing called Table Routing. Using Table Routing, when the SMSC needs to communicate with a specific service user, the SMSC looks up in a table to see which home location register ("HLR") is associated with the specific MIN ID. For each HLR, the lookup table contains a corresponding address, which is made up of a point code and a subsystem number defining the HLR. A problem with the Table Routing method is that as HLRs get taken out of service and/or replaced, the lookup tables of any SMSC that needed to contact that HLR had to be individually changed. In response, a newer, method of addressing called Global Table Translation ("GTT") has been adopted by many networks. In this system, a message can be routed using just the MIN ID and the subsystem number which does not change even if HLRs are moved, replaced or taken out of service. As these two types of networks are integrated, the SMSC must be able to handle both types of addressing. However, conventional SMSCs only provide support for a single type. Thus, the integration of two networks having dissimilar addressing schemes would require separate SMSCs which as discussed above, would impose additional startup, administrative, and maintenance costs.
A further problem associated with integration is that different telecommunications networks have different definitions of a "short" message. The term short message connotes that the length of the message being sent over the network must be short. However, there is no industry-wide standard for the length of the short message, which has lead to various lengths for defining a short message throughout the industry. This may cause a problem when sending messages between networks with differing lengths for a short message. Specifically, a significant problem occurs when sending a short message from a first system having a message length that is larger than the message length for a second system receiving the message. Conventional SMSCs solve this problem using two approaches. In the first approach, the SMSC merely sends the short message without any processing leading to a garbled or incomplete message when the message is truncated by the second system. In the second approach, the service center does not deliver the message to the second system and provides an error code to the first system indicating that the message length is too long. Therefore, conventional SMSCs do not provide a means of sending a completely intact short message between systems having different definitions of a short message.